Scientific consensus tells us that the number of microbes in our bodies exceeds the total number of human cells. These microbes represent 99% of our genetic material! They were here first, have co-evolved with us, and continue to play crucial roles in development as well as lifelong health.
In this article, we will discuss the roles our microbes, commonly referred to as “bugs,” play in brain development, cognitive function and overall wellness throughout different states in life. We will also highlight the supportive role of specialized probiotics or what we now refer to as “psychobiotics.”
A large body of scientific evidence has demonstrated the importance of early life exposure to microbes. These friendly bugs are instrumental to the development of our gut microbiome, immune system, brain and nervous system., In cases where the normal exposure is absent or limited, such as with C-section births, there is a higher risk of developing allergies and autoimmune diseases.
Preclinical studies have also demonstrated that C-section delivery is associated with social impairment and anxiety-like behaviors. And although there is limited human clinical trial data that makes this connection clear, Professor John Cryan, PhD, describes related unpublished data from his lab, where Irish medical students were subjected to humane stressors and their responses were evaluated.
Students born by C-section experienced more significant perceived psychological stress (PSS) as well as exaggerated immunological response, suggesting our brains are indeed influenced by the bugs we meet at birth.
In fact, leading microbiome and gut-brain axis research laboratories have supplied us with convincing data to support this hypothesis. Findings have shown that a lack of resident microbes will negatively impact nerve conduction in the prefrontal cortex of the brain responsible for high level processing.
A bug-free environment is also associated with the disruption of new neuron formation in the hypocampus, the area in the brain responsible for memory and learning. Critical to social behavior, fear and anxiety response, the brain’s amygdala is also altered, both functionally and structurally, by disruptions in the microbiome.
The good news is that activities such as breastfeeding, quality probiotic supplementation and early exposure to helpful bacteria can reduce these risks in C-section babies. Supplemental probiotics and prebiotics can provide for robust microbiome diversity, as well as support normal brain development and function .
As any parent can attest, the adolescent brain undergoes many changes and hormones are not the least of them.
Interestingly, one of the primary gut-to-brain/brain-to-gut communication channels, the hypothalamic-pituitary-adrenal (HPA) axis, is also undergoing its own developmental process during these years. Chronic stressors in adolescence can result in an HPA axis imbalance, impacting cognition, decision making, and mood over the long term.
Here again, there is some good news. A healthy, whole food diet, regular exercise, adequate sleep, and quality probiotic intake can go a long way toward a balanced microbiome and healthy gut-brain axis.
During the childhood and adolescent years, the gut microbiota is dynamic and evolving. Our bug population does, however, get more stable as we enter adulthood. This stability is then followed by reduced diversity with both age and illness.
To explore this phenomenon, a research team developed the human microbiome aging clock. Amazingly, their approach has successfully predicted human age within five years. The data from their lab and others has suggested that age-dependent changes in microbiota diversity may influence frailty, immune response, and related disease onset.
Another key area of interest within the aging brain lies with its resident immune cells. Acting as scavengers within the central nervous system, microglia are the brain’s housekeepers. And what you might think of as independently functioning cells, these microglia are found to be immature and functionally impaired in the absence of a balanced microbiome.
Lastly, it is important to recall that our gut microbes are instrumental in the production of all five human neurotransmitters – GABA, serotonin, acetylcholine, norepinephrine, and dopamine – as these substances play an integral role in mood and cognition across the lifespan.
The Promise of Psychobiotics
First coined by the team of John Cryan and Ted Dinan at the Alimentary Pharmabiotic Center (APC) at University College, Cork (Ireland), the term “psychobiotics” refers to beneficial bacteria (probiotics) or support for such bacteria (prebiotics) that influence bacteria–brain relationships.
Psychobiotics are able to exert anti-anxiety and antidepressant effects through the gut’s own nervous system as well as the immune system. But not all probiotic strains are psychobiotic, and not all probiotic blends claiming psychobiotic characteristics are backed by scientific evidence.
On the other hand, OMNi-BiOTiCÒ STRESS Release is a clinically proven psychobiotic formulation that has demonstrated positive influence in both functional (fMRI) and psychological measures toward improved mood, memory, and stress management.
It is abundantly clear that our bugs play a vital role in our mental function and overall wellbeing over the entire lifespan. And with the American Psychological Association reporting that more than 80% of Americans are still experiencing prolonged stress in 2021, a sound, scientifically based psychobiotic makes all the sense in the world.
 Moya-Pérez A, Luczynski P, Renes IB, et al. Intervention strategies for cesarean section-induced alterations in the microbiota-gut-brain axis. Nutr Rev. 2017;75(4):225-240. doi:10.1093/nutrit/nuw069
 Nash MJ., et al. Early Microbes Modify Immune System Development and Metabolic Homeostasis—The “Restaurant” Hypothesis Revisited, Front Endocrin. 2017;8:349
 Neu J, Rushing J. Cesarean versus vaginal delivery: long-term infant outcomes and the hygiene hypothesis. Clin Perinatol. 2011;38(2):321-331. doi:10.1016/j.clp.2011.03.008
 Ventura-Silva, Silvia Arboleya, et al. Enduring Behavioral Effects Induced by Birth by Caesarean Section in the Mouse. Current Biology. 2020; 30(19):3761-3774.
 The Gut Microbiome: A Key Regulator of the Brain Across the Lifespan. Presenter: John Cryan, PhD, Host: Center for Brain Health. Accessed 27Jan21: https://www.youtube.com/watch?v=99bsp3Cjeck
 Hoban, A., Stilling, R., Ryan, F. et al. Regulation of prefrontal cortex myelination by the microbiota. Transl Psychiatry 6, e774 (2016). https://doi.org/10.1038/tp.2016.42
 Scott GA, Terstege DJ, Vu AP, Law S, Evans A, Epp JR. Disrupted Neurogenesis in Germ-Free Mice: Effects of Age and Sex. Front Cell Dev Biol. 2020;8:407. Published 2020 May 29. doi:10.3389/fcell.2020.00407
 Stilling RM, Ryan FJ, Hoban AE, Shanahan F, Clarke G, Claesson MJ, Dinan TG, Cryan JF. Microbes & neurodevelopment–Absence of microbiota during early life increases activity-related transcriptional pathways in the amygdala. Brain Behav Immun. 2015 Nov;50:209-220. doi: 10.1016/j.bbi.2015.07.009. Epub 2015 Jul 14. PMID: 26184083.
 Mosconi MW, Cody-Hazlett H, Poe MD, Gerig G, Gimpel-Smith R, Piven J. Longitudinal study of amygdala volume and joint attention in 2- to 4-year-old children with autism. Arch Gen Psychiatry. 2009 May;66(5):509-16. doi: 10.1001/archgenpsychiatry.2009.19. PMID: 19414710; PMCID: PMC3156446.
 Janak PH, Tye KM. From circuits to behaviour in the amygdala. Nature. 2015 Jan 15;517(7534):284-92. doi: 10.1038/nature14188. PMID: 25592533; PMCID: PMC4565157.
 Korpela, K., Salonen, A., Vepsäläinen, O. et al. Probiotic supplementation restores normal microbiota composition and function in antibiotic-treated and in caesarean-born infants.Microbiome 6, 182 (2018). https://doi.org/10.1186/s40168-018-0567-4
 McEwen, B. Neurobiological and Systemic Effects of Chronic Stress. Chronic Stress. 2017 Jan-Dec; 1: 2470547017692328.
 O’Toole PW, Jeffery IB. Gut microbiota and aging. Science. 2015 Dec 4;350(6265):1214-5. doi: 10.1126/science.aac8469. PMID: 26785481.
 Galkin F, Aliper A, Putin E, Kuznetsov I, Gladyshev VN, Zhavoronkov A. Human microbiome aging clocks based on deep learning and tandem of permutation feature importance and accumulated local effects. bioRxiv. 2019. 10.1101/507780.
 Jyothi HJ, Vidyadhara DJ, Mahadevan A, Philip M, Parmar SK, Manohari SG, Shankar SK, Raju TR, Alladi PA. Aging causes morphological alterations in astrocytes and microglia in human substantia nigra pars compacta. Neurobiol Aging. 2015 Dec;36(12):3321-3333. doi: 10.1016/j.neurobiolaging.2015.08.024. Epub 2015 Aug 31. PMID: 26433682.
 Wall R., Cryan J.F., Ross R.P., Fitzgerald G.F., Dinan T.G., Stanton C. (2014) Bacterial Neuroactive Compounds Produced by Psychobiotics. In: Lyte M., Cryan J. (eds) Microbial Endocrinology: The Microbiota-Gut-Brain Axis in Health and Disease. Advances in Experimental Medicine and Biology, vol 817. Springer, New York, NY. https://doi.org/10.1007/978-1-4939-0897-4_10
 https://www.apa.org/news/press/releases/2021/02/adults-stress-pandemic. Accessed 1 Feb 2021.